#
# @lc app=leetcode.cn id=468 lang=python3
#
# [468] 验证IP地址
#

# @lc code=start
class Solution:
    def validIPAddress(self, queryIP: str) -> str:
        if queryIP.find(".") != -1:
            # IPv4
            last = -1
            for i in range(4):
                cur = (len(queryIP) if i == 3 else queryIP.find(".", last + 1))
                if cur == -1:
                    return "Neither"
                if not 1 <= cur - last - 1 <= 3:
                    return "Neither"
                
                addr = 0
                for j in range(last + 1, cur):
                    if not queryIP[j].isdigit():
                        return "Neither"
                    addr = addr * 10 + int(queryIP[j])
                
                if addr > 255:
                    return "Neither"
                if addr > 0 and queryIP[last + 1] == "0":
                    return "Neither"
                if addr == 0 and cur - last - 1 > 1:
                    return "Neither"
                
                last = cur
            
            return "IPv4"
        else:
            # IPv6
            last = -1
            for i in range(8):
                cur = (len(queryIP) if i == 7 else queryIP.find(":", last + 1))
                if cur == -1:
                    return "Neither"
                if not 1 <= cur - last - 1 <= 4:
                    return "Neither"

                for j in range(last + 1, cur):
                    if not queryIP[j].isdigit() and not("a" <= queryIP[j].lower() <= "f"):
                        return "Neither"
                
                last = cur
            
            return "IPv6"
# @lc code=end

